the driver and the person sitting in the front passenger seat must wear seat belt 为什么person 后面可以直接加sitting?

sitting in the front passenger seat 作the person的定语,译为坐在前排乘客座位的人.
由于是the person可以主动发出sit这个动作,所以用现在分词形式.
此外,当所修饰的词无法主动发出动作时,就应该用过去分词形式,如：
the money given by your mother.